The present invention relates to a plastic closure for a container, which closure has a sealing closure element that is initially formed with the closure and is later separable therefrom.
The present invention is an improvement upon the closure disclosed in application Ser. No. 485,183, filed July 2, 1974 by Hans Strub, and now U.S. Pat. No. 3,986,646, entitled "Plastic Closure Top for Tins" and assigned to the assignee hereof. The aforesaid application is incorporated herein by reference particularly with respect to its description of the problem to be solved by the invention described therein, its description of the prior art and its description of the manner in which the invention described therein accomplishes the purpose for which that invention is designed.
Summarizing some basic features of the plastic closure disclosed in the aforesaid application, it includes a base ring that is to be introduced into the mouth of the container, a pouring spout through which the contents of the container are emptied, a bellows between these elements and a closure element which is initially integrally formed with and initially seals the closure, which is separated from the closure to initially open the spout and which is adapted to thereafter be emplaced on and to reseal the spout. The entire closure is preferably integrally molded by, for example, an injection molding process. In order to economically manufacture an entire closure, it is desirable to form the closure element for the spout in the same molding or formation process in which the remainder of the closure is formed. Accordingly, the aforesaid application recites that there is integrally molded to the spout a closure element. This element comprises a hollow cylinder intended to fit into the opening of the spout once the closure element is separated from its initially molded connection to the spout. It also comprises a sealing disc which closes the top end of the closure element cylinder and the disc also carries the means by which the closure element is lifted from the spout when the closure element is used to reseal the spout.
The aforesaid application also notes that it is necessary that before the closure element can be used to reclose the spout, it must first be separated from its integrally molded attachment to the open end of the spout. Accordingly, the aforesaid application recites the interposition of a tear line between the free end of the spout and the open end of the closure means cylinder, along which tear line it is intended that the closure element be separated from the spout some time after molding.
It has been found that demarcation or formation of a tear line for separating the closure element from the spout, while effective, still does not provide independent means that facilitates the separation.